Marine Viruses May be Linked to Coral Bleaching

Marine virus outbreaks may be linked to coral bleaching. The new finding could shed some light on environmental stresses and could help scientists better understand what may happen to coral reefs in the future.

In this latest study, the researchers documented a viral outbreak that occurred as corals were bleaching. Coral bleaching occurs when corals eject their zooxanthellae, the symbiotic algae that live in their tissues and conduct photosynthesis. The loss of sugars donated by the algae can leave corals more susceptible to disease or being overgrown by reef competitors, and can result in coral death over time.

"It is well established that bleaching can occur if environmental stress, such as unusually high temperatures, makes the photosynthetic machinery in symbiotic algae go haywire," said Adrienne Simoes Correa, one of the researchers, in a news release. "During this particular event, we saw conditions get tough for coral colonies, then the reef bleached and we observed very high abundances of several kinds of viruses in these corals, all within a period of a few days."

It's possible that viral infection of corals' symbiotic algae may have contributed to the bleaching in these colonies. This finding, in particular, is significant because Earth is experiencing the third recorded incidence of mass coral bleaching on a global scale.

"People all over the world are concerned about long-term coral survival," said Rebecca Vega-Thurber, corresponding study author. "This research suggests that viral infection could be an important part of the problem that until now has been undocumented and has received very little attention."